Method of making metal plugs



J. HALBRITTER. METHOD OF MAKING METAL PLUGS. APPLICATION FILED MAR. 30, 1920.

Patented Aug. 2, 1921.

29y Grok.

UNITED STATES.

JOHN HALBRITTER, or BoSToN, MASSACHUSETTS, ASSIGNOR To WALWoRT'HMAnu PATENT orrlcn.

rAoT'onING COMPANY, 01? BOSTON, MASSAGHUSETT'S, A' Centenarianor MASSA- CHUSETTS.

METHOD OF MAKING METAL PLUGS.

Application filed March 30, 1920.

the accompanyin drawings, forming a part of this specification, in explaining its nature. The present invention relates to a method of making metal plugs having a threaded body adapted to fit within a hole or opemng and a head by which the plug may be turned. Hitherto plugs of this character have been made by casting, the casting afterwardbeing machine-finished. This is a very slow and expensive method and many of the plugs were either misformed or lost durlng the casting.

The object of the present lnvention 1s to do away with casting during the formation of the plug and to make the plug a machinemade proposition. It is found that th1s may be done by the following method which is described in the light of a plug made of steel.

The method can better be described-in the light of the drawings forming a part of thls specification, and in which Figure 1 is a side elevation of the rod or blank from which the plugs are initially formed.

Fig. 2 is a plan of the blank after the first operation has been performed for maklng the plug.

Fig. 3 is a plan of the blank after the next operation has been completed.

Fig. 4: is a plan of the uncompleted plug afterit has been severed from the blank, and

Fig. 5 is a plan ofthe finished plug.

Referring to the drawings 1 represents a rod or blank preferably cylindrical in form and in size conforming to the size of the plug desired to be obtained after the series of o erations have been completed for making t e plug.

The first operation conslsts in making an annular out or incision 2 in the blank or rod. This cut is made at a point removed from the end of the rod by a distance substantially equal to the length of the body of the plug desired to be obtained, 3 representing that portion of the blank forward of the cut, or,

Specificationof "Letters Patent.

Patented Aug; 2, 1921.

Serial 'No. 370,028.

in other words, the unfinished body of the plug.

The annular cut 2 extends-lengthwise of the rod a distance slightly less than the length of the'head-desired to be obtainedin the finished plug, that portion 4 of the rod around which the cut is made representing.

the unfinished head of" the plug.

The endportion 3 of the rod or unfinished body of the plug is then externally threaded and thereby finished, 5 representing the threads cut thereon (see Fig. 3). The'finished body and'unfinishedhead of the plug is then out from the rod by an incision 6 made at the inner end of the annular cut 2 and there is accordingly obtained the plug as shown in Fig. 4: provided with an unfinished or circular head anda'finished body.

The next operation-consists in finishing.

the head of the plug by squaring or otherwise forming it as may be desired. This is effected by pressure the head being formed or shaped by an application of force applied laterally thereto. This forming of the head by lateral pressure may be successfully accomplished without disturbing the threads on the body of the plug especially those just adjacent the head, owing to the fact that the head contains less metal measured diametrically than the body and the application of force laterally for forming the head tends only to lengthen it without disturbing the body and threads upon it. In this connection care should be taken that the annular cut 2 initially made in the rod should be so deep or so much metal should be removed that the application of pressure laterally to the head will not disturb the threads on the body. For example, with a steel rod a depth of cut of at least 3 2 should be made or otherwise the pressure applied to the head will tend to disturb the threads on the body and spoil the plug. After pressing up the head there is obtained the finished plug as shown in Fig. 5.

The series of operations above referred to may be effected in any suitable manner. These operations apart from the pressing up of the head are such that they may be successfully and automatically accomplished upon a turret lathe or better upon a screw machine. The pressing up of the head may be effected by any one of a variety of well known types of presses.

Having thus fully described my invention, I claim and desire to secure by Letters Patent of the United States l. The method of making metal plugs which comprises the inoising of a metal rod at a point removed from the end of the rod. a distance substantially equal to the length of the body of the plug desired to be obtained whereby forward of said cut there is left a portion of the rod forming the unfinished body of the plug and back of said body a portion of the rod forming the unfinished head of the plug, externally thread ing the unfinished body of the plug and thereby finishing the same, cutting the then finished body and unfinished head of the plug from the rod, and shaping and thereby finishing the head by application of pressure laterally thereto.

2. The method of making metal plugs which comprises the incising of a metal rod at a point removed from the end of the rod a distance substantially equal to the length of the body of the plug desired to be obtained whereby forward of said out there is left a portion of the rod forming the unfinished body of the plug and back of said body a portion of the rod forming the unfinished head of the plug, externally threading the unfinished body of the plug and thereby finishing the same, cutting the then finishedbody and unfinished head of the plug from the rod, and shaping and thereby finishing the head by application of pressure laterally thereto, the incision initially made in the rod being in suchamount as to leave in the unfinished head of the plug such lesser amount of metal than in said finished body of the plug as to avoid the upsetting of the threads on the body of the plug adjacent said head upon the application of lateral pressure for shaping the head as aforesaid.

3. The method of making metal plugs which comprises the steps of incising a metal blank at a point removed from the end of the blank a distance substantially equal to the length of the body of the plug desired to be obtained whereby forward 01"" said incision there is left a portion of the blank forming the unfinished body of the plug and back of said body a portion of the blank of lesser diameter than the body and forming the unfinished head of the blank, externally threading the unfinished body of the plug and thereby finishing it and shaping and thereby finishing the head by application of pressure laterally thereto.

JOHN HALBRITTER. 

